There is plenty water in the oceans, but I've read that deep in the crust/mantle of the earth within crystals and other rockforms is water enclosed. So could it be possible that there is more water beneath the surface of the earth than above?

  • $\begingroup$ Most of the Earth's water is stored in the form of ice at the poles and mountains. $\endgroup$ – Gemechu Fanta Garuma Jun 28 '16 at 16:21
  • $\begingroup$ Did you search other places for your question? It is pretty obvious question . For example you can look at this link water.usgs.gov/edu/earthwherewater.html $\endgroup$ – Gemechu Fanta Garuma Jun 28 '16 at 16:29
  • $\begingroup$ Well I mean not water in mountains in ice form or on the poles. But there are eg diamonds found with a bit of water in it, so what I mean is really deep earth in the mantle $\endgroup$ – Marijn Jun 28 '16 at 16:46
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    $\begingroup$ @GFG That is definitely not true. Most of the Earth's freshwater is locked up in ice caps but freshwater is only a tiny fraction of the total amount of water on the Earth. $\endgroup$ – bon Jun 28 '16 at 18:58
  • $\begingroup$ Here are good papers: Faccenda 2014 and Nishi 2014 It's a rather hot topic and interesting interdisciplinary research is ongoing. I think that reliable models that try to quantify the mantle water is coming, but I won't hold my breath. $\endgroup$ – Tactopoda Aug 3 '16 at 11:22

Clearly you are referring to water locked up in hydrous minerals. The short answer is no, not much water in the Earth at all compared to the surface. The hotter it gets the more hydrous minerals tend to dehydrate, so there are only minuscule traces of water at great depth. I suggest you calculate a rough water balance of water carried into subduction zones = length of subduction zone x thickness x sediment porosity (under pressure) x average subduction rate. This should be compared with estimates of volcanic emission of water vapour (both to the atmosphere and submarine - more difficult to estimate). I'm guessing these should be more or less in equilibrium. The water volume involved is trivial compared to the water on the oceans.

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    $\begingroup$ I'm not sure that's true, though there's a good deal of uncertainty on how much water exists in the Earth's crust and mantle, it's entirely possible that it's just as much as on the surface. Some people think so, anyway. smithsonianmag.com/smart-news/… and natureworldnews.com/articles/7560/20140613/… $\endgroup$ – userLTK Jun 29 '16 at 5:06
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    $\begingroup$ @userLTK indeed. Also after attending this year's Goldschmidt conference, it seems that people are figuring out more and more ways in which water can be hosted (as H2, OH or H2O) in the mantle. $\endgroup$ – Gimelist Jul 6 '16 at 12:02

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